Battle of Resafa

The Battle of Resafa (55 BC) was a battle of the Roman-Parthian Wars fought between the Roman Republic and Parthia in present-day Raqqa Governorate, eastern Syria. The 1,862-strong Roman army of Decimus Canidius Faustillus defeated Jahanmehr's 1,904-strong army of Parthia with 83 losses, inflicting 1,491 losses on Parthia.

History
The Roman Republic and Parthia were enemies since 66 BC, when Pompey the Great invaded Armenia in an act that led to over 600 more years of war with Persian dynasties. Decimus Canidius Faustillus was dispatched wtih 1,862 Roman troops to defend Roman Syria in 60 BC while Julius Caesar and most of Rome's legions waged war in Gaul against the Arverni, Helvetii, Boii, Suebi, and other tribes in the area. In 55 BC, Parthian general Jahanmehr and 1,904 troops marched into Syria to conquer the region, believing that Caesar's absence would help them. However, they engaged the Romans in the grasslands of Raqqa Governorate at Resafa. Faustillus' army included several cavalry units, Armored Legionnaries with swords and shields, triarii spearmen, and auxiliary ranged units from the Balearic Isles and Syria. The Parthian army was mostly hillmen, having a few spearmen and slingers.

Battle
The Roman army was deployed against the Parthians with cavalry on either flank, with the Roman missile units being kept behind the first line of melee infantry. The Parthians attacked the Roman army, but the Roman right flank cavalry charged and took out the Parthian units on that side, allowing for them to attack other Parthian units as the main Parthian army engaged the Romans in melee. The weaker Parthian hillmen were slain by the armored Roman legionnaries, who hacked them to death with their steel swords. The Parthian army collapsed, but the Roman cavalry decided to pursue them, as did the infantry. The Roman cavalry rode down the retreating Parthians, killing most of them.